E46 DIY Differential Swap

These instructions are only as a guide for people to swap differentials. Please read through all the instructions before attempting to install on your own. I take no responsibilities for any inaccuracies or problems/damage /injuries you may encounter from using these instructions. Please consult your shop manual. Sorry about the poor photos. I wasn’t planning on doing a differential write up. Most of the pictures were taken after I installed the differential. That said… lets begin.

7. Remove the Differential. Support the differential with a jack. The Differential is held down by 3 bolts. 2 18mm bolts in the front, 21mm bolt on the rear. Remove the 2 front ones first (Figure F), then remove the rear one (Figure J). (Tightening torque – 18mm Bolts 70 ft-lbs, 21mm Bolt 128ft-lbs) (when reinstalling, insert all 3 bolts finger tight. Tighten the 2 front bolts first, then tighten down the rear bolt).
Work the differential off the car by pulling it towards the rear end. Slowly lower the jack as you pull it out. (you need 2 people for this part.)

8. Since the new differential is off the car. Now is the ideal time to fill up the differential. The drain/fill plugs use a 14mm hex wrench. (Figure A) It's hard to find. so I used a nut and bolt that was 14mm in diameter instead. Click here for my DIY 14mm hex socket. Use the new seal rings after filling up the differential with new gear oil. (Tightening torque 14mm plug 52 ft –lbs).

Note: I just used Mobil 1 Synthetic 75/90 gear oil since that's what they had at Pep Boys. (oil specification BMW SAF-XO synthetic oil. 0.95 US qt)